Techniques are provided to fabricate semiconductor devices having a nanosheet field-effect transistor device disposed on a semiconductor substrate. The nanosheet field-effect transistor device includes a nanosheet stack structure including a semiconductor channel layer and a source/drain region in contact with an end portion of the semiconductor channel layer of the nanosheet stack structure. A trench formed in the source/drain region is filled with a metal-based material. The metal-based material filling the trench in the source/drain region mitigates the effect of source/drain material overfill on the contact resistance of the semiconductor device.
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1. A method for fabricating a semiconductor device, comprising: forming a nanosheet stack structure on a semiconductor substrate, wherein the nanosheet stack structure comprises a semiconductor channel layer; forming a gate structure on the nanosheet stack structure; forming a source/drain region in contact with an end portion of the semiconductor channel layer of the nanosheet stack structure; forming a sacrificial layer on a top surface of the source/drain region and sidewalls of the gate structure to define an opening; depositing an interlevel dielectric layer in the opening; etching a trench in the source/drain region through the interlevel dielectric layer and at least a portion of the sacrificial layer on the top surface of the source/drain region; removing a remaining portion of the sacrificial layer on the sidewalls of the gate structure after etching the trench; and filling the trench with a metal-based material.
This invention relates to semiconductor device fabrication, specifically addressing challenges in forming high-performance source/drain contacts in nanosheet-based transistors. The method involves creating a nanosheet stack structure on a semiconductor substrate, where the stack includes a semiconductor channel layer. A gate structure is then formed over the nanosheet stack, followed by the formation of source/drain regions that contact the ends of the semiconductor channel layer. A sacrificial layer is deposited on the top surface of the source/drain regions and the sidewalls of the gate structure, defining an opening. An interlevel dielectric layer is deposited into this opening. A trench is etched through the interlevel dielectric layer and at least part of the sacrificial layer on the source/drain region. The remaining sacrificial layer on the gate sidewalls is removed after trench etching. Finally, the trench is filled with a metal-based material to form a conductive contact. This process ensures precise alignment and low-resistance connections to the source/drain regions, improving device performance and reliability in advanced semiconductor manufacturing.
2. The method of claim 1 , wherein the trench extends to a depth in the source/drain region at least equal to a depth of the semiconductor channel layer in the nanosheet stack structure.
This invention relates to semiconductor device fabrication, specifically to the formation of trench structures in nanosheet-based transistors. The problem addressed is achieving precise control of trench depth during etching to ensure proper electrical isolation and performance in advanced semiconductor devices. The method involves forming a trench in a source/drain region of a semiconductor structure containing a nanosheet stack. The trench is etched to a depth that is at least equal to the depth of the semiconductor channel layer within the nanosheet stack. This ensures the trench fully penetrates the channel region, preventing unintended electrical coupling between adjacent devices. The nanosheet stack typically includes alternating layers of semiconductor and sacrificial material, where the sacrificial layers are later removed to form the channel regions. The trench depth control is critical to avoid damaging underlying layers while ensuring complete isolation. The method may also include forming spacers or other isolation structures within the trench to enhance electrical performance. This approach is particularly useful in finFET or nanosheet transistor architectures where precise dimensional control is essential for device functionality.
3. The method of claim 1 , wherein forming the source/drain region comprises epitaxially growing semiconductor material on the end portion of the semiconductor channel layer.
This invention relates to semiconductor device fabrication, specifically to forming source/drain regions in a transistor structure. The problem addressed is improving the electrical performance and reliability of transistors by optimizing the source/drain regions. The method involves epitaxially growing semiconductor material on the end portions of a semiconductor channel layer to form the source/drain regions. This growth process enhances carrier mobility and reduces contact resistance, improving overall device efficiency. The semiconductor material used for epitaxial growth is selected to match or complement the channel material, ensuring lattice compatibility and minimizing defects. The process may include pre-cleaning the channel surface to ensure proper adhesion and growth quality. The epitaxial growth can be performed using techniques such as chemical vapor deposition (CVD) or molecular beam epitaxy (MBE), with precise control over doping levels to achieve desired electrical properties. The resulting source/drain regions have improved strain engineering, which enhances carrier transport and device performance. This method is particularly useful in advanced semiconductor nodes, such as FinFETs or nanowire transistors, where precise control of material properties is critical. The invention provides a scalable solution for high-performance transistors in integrated circuits.
4. The method of claim 3 , wherein forming the source/drain region comprises epitaxially growing semiconductor material on the end portion of the semiconductor channel layer and on a portion of the semiconductor substrate.
This invention relates to semiconductor device fabrication, specifically to methods for forming source/drain regions in transistors. The problem addressed is improving the electrical performance and reliability of transistors by optimizing the structure and formation of source/drain regions. The method involves forming a semiconductor channel layer on a semiconductor substrate, where the channel layer has an end portion. A source/drain region is then formed by epitaxially growing semiconductor material on both the end portion of the channel layer and a portion of the underlying substrate. This growth process creates a continuous, high-quality semiconductor region that enhances charge carrier mobility and reduces resistance at the source/drain interfaces. The epitaxial growth ensures precise control over the material properties, such as doping concentration and crystal structure, which are critical for device performance. The technique is particularly useful in advanced transistor designs, such as FinFETs or nanowire transistors, where precise control of the source/drain regions is essential for achieving high drive current and low leakage. By growing the semiconductor material on both the channel layer and the substrate, the method improves the mechanical stability and electrical connectivity of the source/drain regions, leading to more reliable and efficient transistors. The epitaxial growth process can be tailored to match the lattice structure of the channel material, minimizing defects and enhancing overall device performance.
5. The method of claim 3 , wherein forming the source/drain region comprises epitaxially growing semiconductor material on the end portion of the semiconductor channel layer and on a portion of an oxide layer formed over a portion of the semiconductor substrate.
This invention relates to semiconductor device fabrication, specifically to methods for forming source/drain regions in transistors. The problem addressed is improving the performance and reliability of semiconductor devices by optimizing the formation of source/drain regions in advanced transistor structures. The method involves epitaxially growing semiconductor material on the end portion of a semiconductor channel layer and on a portion of an oxide layer formed over a portion of the semiconductor substrate. The semiconductor channel layer is part of a transistor structure, typically a fin or nanowire in a FinFET or gate-all-around (GAA) transistor. The oxide layer acts as an insulating layer, and the epitaxial growth extends onto both the channel layer and the oxide layer to form the source/drain regions. This approach enhances the electrical connection between the source/drain regions and the channel while maintaining isolation from the underlying substrate. The epitaxial growth may include in-situ doping to adjust conductivity, and the process may involve selective growth techniques to ensure precise material deposition. This method improves carrier mobility and reduces parasitic capacitance, leading to better transistor performance.
6. The method of claim 5 , wherein the trench extends through the source/drain region to the oxide layer.
A method for semiconductor device fabrication involves forming a trench that extends through a source/drain region to an underlying oxide layer. This trench formation is part of a process for creating a semiconductor structure, where the trench is used to isolate or connect components within the device. The oxide layer serves as an insulating barrier, and the trench's depth ensures it reaches this layer to achieve the desired electrical or structural properties. The method may include additional steps such as etching, deposition, or planarization to define the trench's dimensions and ensure proper integration with other device features. This approach is particularly useful in advanced semiconductor manufacturing, where precise control over trench depth and alignment is critical for device performance and reliability. The trench may be formed using techniques such as dry etching or plasma etching, with careful process parameters to avoid damaging adjacent structures. The resulting structure enables improved isolation, reduced parasitic capacitance, or enhanced electrical connectivity, depending on the specific application. This method is applicable to various semiconductor devices, including transistors, memory cells, and integrated circuits, where precise trench formation is essential for optimal functionality.
7. The method of claim 1 , further comprising: forming a dummy gate structure over the nanosheet stack structure; forming a gate insulating spacer on vertical sidewalls of the dummy gate structure, wherein end portions of the semiconductor channel layer are exposed through the gate insulating spacer; removing the dummy gate structure to form a gate recess region that exposes a portion of the nanosheet stack structure surrounded by the gate insulating spacer; etching at least the portion of the nanosheet stack structure in the gate recess region to form a space between the semiconductor channel layer and at least one other layer of the nanosheet stack structure; and forming a metal gate structure within the gate recess region.
This invention relates to semiconductor device fabrication, specifically to methods for forming a metal gate structure in a nanosheet-based transistor. The problem addressed is the precise formation of a gate structure around a semiconductor channel layer in a nanosheet stack, ensuring proper isolation and electrical contact while maintaining structural integrity. The method involves forming a dummy gate structure over a nanosheet stack, which includes multiple layers, at least one of which is a semiconductor channel layer. A gate insulating spacer is then formed on the vertical sidewalls of the dummy gate, exposing the end portions of the semiconductor channel layer. The dummy gate is removed, creating a gate recess region that exposes the portion of the nanosheet stack surrounded by the spacer. The exposed portion of the nanosheet stack is etched to create a space between the semiconductor channel layer and at least one adjacent layer, allowing for selective deposition of materials. Finally, a metal gate structure is formed within the gate recess region, surrounding the semiconductor channel layer while maintaining isolation from other layers in the stack. This process ensures precise gate formation and proper electrical isolation in nanosheet-based transistors.
8. The method of claim 1 , wherein forming the nanosheet stack structure on the semiconductor substrate comprises: epitaxially growing a sacrificial nanosheet layer on the semiconductor substrate; epitaxially growing the semiconductor channel layer on the sacrificial nanosheet layer; and patterning the sacrificial nanosheet layer and the semiconductor channel layer to form the nanosheet stack structure.
This invention relates to semiconductor device fabrication, specifically the formation of nanosheet-based transistors. The technology addresses challenges in creating high-performance, scaled-down transistors by improving the structural integrity and uniformity of nanosheet stack structures. The method involves forming a nanosheet stack structure on a semiconductor substrate. First, a sacrificial nanosheet layer is epitaxially grown on the substrate. This layer serves as a temporary support for subsequent layers. Next, a semiconductor channel layer is epitaxially grown on top of the sacrificial layer. The channel layer will later form the active region of the transistor. The sacrificial and channel layers are then patterned together to create the nanosheet stack structure, which consists of alternating layers of sacrificial and channel material. This patterned structure is used to define the transistor's channel region, enabling precise control over device dimensions and performance. The sacrificial layer ensures proper alignment and stability during processing, while the channel layer provides the necessary electrical properties for transistor operation. The patterning step defines the final geometry of the nanosheet stack, which is critical for achieving optimal device characteristics. This approach enhances manufacturing consistency and improves transistor performance in advanced semiconductor devices.
9. The method of claim 7 , wherein the source/drain region is formed in contact with at least a portion of the gate insulating spacer, and wherein the sacrificial layer is formed in contact with at least a portion of the gate insulating spacer.
This invention relates to semiconductor device fabrication, specifically to methods for forming source/drain regions and gate structures in transistors. The problem addressed is optimizing the interface between the source/drain regions, gate insulating spacers, and sacrificial layers to improve device performance and reliability. The method involves forming a gate insulating spacer adjacent to a gate structure. A source/drain region is then formed such that it makes direct contact with at least a portion of this gate insulating spacer. Additionally, a sacrificial layer is deposited in a way that it also contacts at least a portion of the gate insulating spacer. The sacrificial layer may serve as a placeholder for subsequent processing steps, such as epitaxial growth or doping, to enhance the source/drain region's properties. The direct contact between the source/drain region and the gate insulating spacer ensures proper electrical isolation and reduces parasitic capacitance, while the sacrificial layer's contact with the spacer facilitates precise alignment and structural integrity during further fabrication steps. This approach improves transistor performance by minimizing leakage and enhancing charge carrier mobility.
10. A method for fabricating a semiconductor device, comprising: forming a nanosheet stack structure on a semiconductor substrate, wherein the nanosheet stack structure comprises a stack of alternating semiconductor layers which comprises sacrificial nanosheet layers and nanosheet channel layers, wherein each nanosheet channel layer is disposed between sacrificial nanosheet layers in the nanosheet stack structure; forming a dummy gate over the nanosheet stack structure to define a gate region; forming a gate sidewall spacer surrounding the dummy gate; forming a source/drain region in contact with end portions of the nanosheet channel layers of the nanosheet stack structure; forming a sacrificial layer on a top surface of the source/drain region and sidewalls of the gate sidewall spacer to define an opening; depositing an interlevel dielectric layer in the opening; etching a trench in the source/drain region through the interlevel dielectric layer and at least a portion of the sacrificial layer on the top surface of the source/drain region; removing a remaining portion of the sacrificial layer on the sidewalls of the gate sidewall spacer after etching the trench; and filling the trench with a metal-based material.
This invention relates to semiconductor device fabrication, specifically a method for forming a nanosheet-based transistor structure. The method addresses challenges in integrating nanosheet architectures with advanced source/drain contact schemes, particularly in ensuring reliable electrical connections while maintaining structural integrity during processing. The process begins by forming a nanosheet stack on a semiconductor substrate, consisting of alternating sacrificial and channel layers. A dummy gate is then formed over the stack to define the transistor's gate region, followed by gate sidewall spacers. Source/drain regions are formed at the ends of the nanosheet channel layers. A sacrificial layer is deposited on the source/drain region and spacer sidewalls, creating an opening that is filled with an interlevel dielectric. A trench is etched through the dielectric and into the source/drain region, followed by selective removal of the sacrificial layer from the spacer sidewalls. This exposes the nanosheet channel layers for subsequent processing. The trench is then filled with a metal-based material to form a robust electrical contact to the source/drain region and underlying nanosheet channels. This approach enables precise control over contact formation while minimizing damage to the delicate nanosheet structure, improving device performance and yield in advanced semiconductor manufacturing.
11. The method of claim 10 , wherein the trench extends to a depth in the source/drain region at least equal to a depth of the nanosheet channel layer in the nanosheet stack structure.
This invention relates to semiconductor device fabrication, specifically to methods for forming trenches in nanosheet-based transistor structures. The problem addressed is ensuring proper electrical isolation and structural integrity in advanced nanosheet transistors, where precise trench depth control is critical to avoid damaging the nanosheet channel layers while maintaining effective source/drain region isolation. The method involves etching a trench into a semiconductor substrate containing a nanosheet stack structure, which includes multiple nanosheet channel layers stacked vertically. The trench extends into the source/drain region adjacent to the nanosheet stack. The key innovation is controlling the trench depth such that it reaches at least the same depth as the lowest nanosheet channel layer in the stack. This ensures the trench fully isolates the source/drain region without undercutting or damaging the active channel layers, which could degrade transistor performance. The technique may involve selective etching processes that stop at or just below the deepest nanosheet channel layer, using etch stop layers or timing-based etch control. This approach is particularly useful in FinFET or nanosheet transistor architectures where precise dimensional control is essential for maintaining device reliability and performance in advanced semiconductor nodes.
12. The method of claim 10 , wherein forming the source/drain region comprises epitaxially growing semiconductor material on the end portions of the nanosheet channel layer and on a portion of the semiconductor substrate.
This invention relates to semiconductor device fabrication, specifically methods for forming source/drain regions in nanosheet-based transistors. The problem addressed is the need for efficient and precise formation of source/drain regions in advanced nanoscale transistors, particularly those using nanosheet channel architectures. The method involves epitaxially growing semiconductor material on exposed end portions of a nanosheet channel layer and on adjacent portions of the semiconductor substrate. The nanosheet channel layer is a thin, horizontal semiconductor layer suspended between vertical support structures, forming the conductive channel of the transistor. The epitaxial growth process selectively deposits semiconductor material on these exposed regions, creating raised source/drain regions that are self-aligned to the nanosheet channel. This approach improves electrical contact between the source/drain regions and the nanosheet channel while maintaining precise dimensional control. The epitaxial growth may use silicon, silicon-germanium, or other semiconductor compounds, depending on the desired device properties. The method ensures uniform material deposition and minimizes defects, enhancing device performance and reliability. This technique is particularly useful for advanced logic and memory devices requiring high mobility channels and low resistance contacts.
13. The method of claim 10 , wherein forming the source/drain region comprises epitaxially growing semiconductor material on the end portions of the nanosheet channel layer and on a portion of an oxide layer formed over a portion of the semiconductor substrate, and wherein the trench extends through the source/drain region to the oxide layer.
This invention relates to semiconductor device fabrication, specifically to methods for forming source/drain regions in nanosheet-based transistors. The problem addressed is the integration of epitaxial source/drain regions with nanosheet channel structures while ensuring proper electrical isolation and structural stability. The method involves forming a trench in a semiconductor substrate, where the trench exposes end portions of a nanosheet channel layer. Semiconductor material is then epitaxially grown on these exposed end portions, as well as on a portion of an oxide layer that is formed over part of the substrate. The trench extends through the epitaxially grown source/drain region to reach the underlying oxide layer, which provides electrical isolation. The oxide layer prevents short-circuiting between the source/drain regions and the substrate while maintaining structural support for the nanosheet channel. This approach ensures proper electrical connectivity between the source/drain regions and the nanosheet channel while minimizing parasitic capacitance and leakage currents. The epitaxial growth process is carefully controlled to achieve uniform material deposition and optimal device performance.
14. The method of claim 10 , wherein forming the dummy gate over the nanosheet stack structure to define the gate region; comprises: forming a dummy gate structure over the nanosheet stack structure; forming a gate insulating spacer on vertical sidewalls of the dummy gate structure, wherein end portions of the nanosheet channel layers are exposed through the gate insulating spacer; removing the dummy gate structure to form a gate recess region that exposes a portion of the nanosheet stack structure surrounded by the gate insulating spacer; etching at least the portion of the nanosheet stack structure in the gate recess region to form a space between the nanosheet channel layer and at least one other layer of the nanosheet stack structure; and forming a metal gate structure within the gate recess region.
This invention relates to semiconductor device fabrication, specifically to methods for forming a metal gate structure in a nanosheet-based transistor. The problem addressed is the precise formation of a metal gate around nanosheet channel layers while ensuring proper isolation and electrical contact. The method involves forming a dummy gate structure over a nanosheet stack, which includes multiple nanosheet channel layers. A gate insulating spacer is then formed on the vertical sidewalls of the dummy gate, exposing the end portions of the nanosheet channel layers. The dummy gate is removed, creating a gate recess region that exposes a portion of the nanosheet stack. The exposed portion of the nanosheet stack is etched to create a space between the nanosheet channel layer and adjacent layers, allowing for precise gate formation. Finally, a metal gate structure is formed within the gate recess region, ensuring proper electrical contact to the nanosheet channel layers while maintaining isolation from other layers. This approach improves gate formation accuracy and device performance in nanosheet-based transistors.
15. The method of claim 14 , wherein the source/drain region is formed in contact with at least a portion of the gate insulating spacer, and wherein the sacrificial layer is formed in contact with at least a portion of the gate insulating spacer.
This invention relates to semiconductor device fabrication, specifically to methods for forming source/drain regions and sacrificial layers in contact with gate insulating spacers. The technology addresses challenges in integrating these components while maintaining precise alignment and structural integrity during device manufacturing. The method involves forming a gate structure with insulating spacers on its sidewalls. A source/drain region is then created in direct contact with at least a portion of these spacers. Additionally, a sacrificial layer is deposited, also in contact with at least a portion of the same spacers. This configuration ensures proper electrical isolation and structural support while allowing for subsequent processing steps, such as etching or material deposition, without compromising device performance. The sacrificial layer may be used to protect underlying structures during etching or as a placeholder for later material integration. The direct contact between the source/drain region, sacrificial layer, and gate spacers ensures tight dimensional control and minimizes defects. This approach is particularly useful in advanced semiconductor nodes where precise feature alignment is critical for device functionality. The method improves manufacturing yield and reliability by reducing misalignment and material degradation during fabrication.
16. The method of claim 10 , wherein forming the nanosheet stack structure on the semiconductor substrate comprises: epitaxially growing a sacrificial nanosheet layer on the semiconductor substrate; epitaxially growing the nanosheet channel layer on the sacrificial nanosheet layer; and patterning the sacrificial nanosheet layer and the nanosheet channel layer to form the nanosheet stack structure.
This invention relates to semiconductor device fabrication, specifically the formation of nanosheet stack structures for advanced transistors. The technology addresses challenges in creating high-performance, scaled-down transistors by improving the precision and control of nanosheet layer formation. The method involves epitaxially growing a sacrificial nanosheet layer directly on a semiconductor substrate, followed by epitaxial growth of a nanosheet channel layer on top of the sacrificial layer. Both layers are then patterned to form a nanosheet stack structure. The sacrificial layer serves as a temporary support during processing, allowing precise formation of the channel layer, which will later function as the active region of the transistor. This approach enables better control over the thickness and uniformity of the nanosheet layers, critical for optimizing transistor performance in nanoscale devices. The patterning step defines the final structure, ensuring alignment and dimensional accuracy. The sacrificial layer can later be selectively removed, leaving the channel layer intact for further device integration. This technique is particularly useful in fabricating gate-all-around (GAA) transistors, where multiple nanosheets are stacked to enhance current flow and reduce leakage. The method improves manufacturing yield and device reliability by minimizing defects and ensuring consistent layer properties.
17. A method for fabricating a semiconductor device, comprising: forming a nanosheet stack structure on a semiconductor substrate, wherein the nanosheet stack structure comprises a semiconductor channel layer; forming a dummy gate structure over the nanosheet stack structure; forming a gate insulating spacer on vertical sidewalls of the dummy gate structure, wherein end portions of the semiconductor channel layer are exposed through the gate insulating spacer; forming an oxide layer over a portion of the semiconductor substrate; forming a source/drain region on a portion of the oxide layer formed over the portion of the semiconductor substrate, in contact with an end portion of the semiconductor channel layer of the nanosheet stack structure and in contact with at least a portion of the gate insulating spacer; forming a sacrificial layer on a top surface of the source/drain region and in contact with at least a portion of sidewalls of the gate insulating spacer to define an opening; depositing an interlevel dielectric layer in the opening; removing the dummy gate structure to form a gate recess region that exposes a portion of the nanosheet stack structure surrounded by the gate insulating spacer; etching at least the portion of the nanosheet stack structure in the gate recess region to form a space between the semiconductor channel layer and at least one other layer of the nanosheet stack structure; forming a metal gate structure within the gate recess region; etching a trench in the source/drain region through the interlevel dielectric layer and at least a portion of the sacrificial layer on the top surface of the source/drain region, the trench extending through the source/drain region to the oxide layer; and filling the trench with a metal-based material.
This invention relates to semiconductor device fabrication, specifically for nanosheet-based transistors. The method addresses challenges in forming high-performance nanosheet field-effect transistors (FETs) with improved source/drain contacts and gate structures. The process begins by forming a nanosheet stack on a semiconductor substrate, including a semiconductor channel layer. A dummy gate is then formed over the stack, followed by a gate insulating spacer that exposes the channel layer's end portions. An oxide layer is deposited on the substrate, and a source/drain region is formed on the oxide, contacting the channel layer and the gate spacer. A sacrificial layer is then deposited on the source/drain region, defining an opening filled with an interlevel dielectric. The dummy gate is removed to create a gate recess, and the nanosheet stack is etched to form a space between the channel layer and adjacent layers. A metal gate structure is then formed in the recess. A trench is etched through the source/drain region, extending to the oxide layer, and filled with a metal-based material to enhance electrical contact. This method improves device performance by optimizing gate and source/drain configurations in nanosheet transistors.
18. The method of claim 17 , wherein the trench extends to a depth in the source/drain region at least equal to a depth of the semiconductor channel layer in the nanosheet stack structure.
This invention relates to semiconductor device fabrication, specifically to the formation of trench structures in nanosheet-based transistors. The problem addressed is controlling the depth of trenches in source/drain regions to ensure proper electrical contact while avoiding damage to the underlying semiconductor channel layers. The invention describes a method where a trench is formed in a source/drain region of a semiconductor device, extending to a depth at least equal to the depth of the semiconductor channel layer within a nanosheet stack structure. The nanosheet stack structure comprises multiple semiconductor channel layers separated by sacrificial layers. The trench formation process involves etching through the source/drain region and stopping at or beyond the deepest semiconductor channel layer to ensure full exposure for subsequent contact formation. This ensures reliable electrical connection while preventing over-etching that could damage the channel layers. The method is particularly useful in advanced nanoscale transistors where precise control of trench depth is critical for performance and reliability. The invention may be applied in FinFET or nanosheet-based CMOS technologies for high-performance integrated circuits.
19. The method of claim 17 , wherein forming the source/drain region comprises epitaxially growing semiconductor material on the end portion of the semiconductor channel layer and on the portion of the oxide layer formed over the portion of the semiconductor substrate.
This invention relates to semiconductor device fabrication, specifically to methods for forming source/drain regions in transistor structures. The problem addressed is improving the integration of source/drain regions with high-k dielectric materials and semiconductor channel layers, particularly in advanced transistor architectures. The method involves forming a source/drain region by epitaxially growing semiconductor material on both the end portion of a semiconductor channel layer and on a portion of an oxide layer that has been formed over a portion of the semiconductor substrate. The semiconductor channel layer is typically part of a transistor structure, and the oxide layer may be a high-k dielectric material used in gate insulation. The epitaxial growth ensures a continuous and uniform source/drain region that interfaces with both the channel layer and the underlying oxide layer, improving electrical performance and reliability. This approach is particularly useful in finFET or gate-all-around transistor architectures where precise control of the source/drain interface is critical. The method may also include forming a gate structure adjacent to the channel layer and source/drain regions, with the gate structure including additional dielectric and conductive materials. The epitaxial growth process is carefully controlled to ensure proper material composition and strain engineering, which can enhance carrier mobility in the channel. This technique helps address challenges in scaling transistor dimensions while maintaining performance and reliability.
20. The method of claim 17 , wherein the source/drain region is formed in contact with the portion of the oxide layer formed over the portion of the semiconductor substrate.
This invention relates to semiconductor device fabrication, specifically to methods for forming source/drain regions in contact with an oxide layer over a semiconductor substrate. The problem addressed is optimizing the interface between source/drain regions and underlying oxide layers to improve device performance and reliability. The method involves forming an oxide layer over a semiconductor substrate, where the oxide layer has a portion that remains exposed. A source/drain region is then formed in direct contact with this exposed portion of the oxide layer. This ensures proper electrical and structural integration between the source/drain region and the oxide layer, which is critical for transistor operation. The process may include steps such as etching to define the oxide layer, deposition of source/drain material, and annealing to enhance material properties. The invention improves upon prior techniques by ensuring precise alignment and contact between the source/drain region and the oxide layer, reducing defects and improving charge carrier mobility. This is particularly useful in advanced semiconductor devices where interface quality directly impacts performance. The method may be applied in various semiconductor technologies, including CMOS and FinFET structures, to enhance device efficiency and longevity.
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March 1, 2019
March 29, 2022
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